How to Shut Off Your Water in a Plumbing Emergency

When a pipe bursts, a water heater starts leaking, or a supply line connection fails, shutting off the water is the first and most important thing you can do. Every minute of delay means more water on your floors, walls, and belongings. Yet many homeowners do not know where their shutoff valve is or how to operate it until they are standing in a growing puddle searching frantically.

Take five minutes now to locate and test your shutoff valve. That small investment of time can prevent thousands of dollars in water damage when an emergency occurs.

Where to Find Your Main Shutoff Valve

In most San Carlos homes, the main water shutoff valve is located where the main water supply line enters the house. Common locations include inside the garage near the front wall, in a utility closet, in a crawl space near the foundation, or on an exterior wall near the front of the house.

If you cannot find the interior shutoff, look for the street-side shutoff at the water meter. The meter is typically located in a rectangular box near the curb or sidewalk in front of your home. The shutoff will be on the house side of the meter — it may require a meter key or adjustable wrench to turn.

How to Operate the Valve

You will find one of two types of valves. A gate valve has a round wheel-shaped handle — turn it clockwise to close. It may take several full rotations. A ball valve has a lever handle — rotate it 90 degrees so the handle is perpendicular to the pipe to close it. Ball valves are faster and more reliable than gate valves.

If the valve is stiff or hard to turn, apply gentle steady pressure. Do not use excessive force or a large wrench, as old valves can break. If it will not budge, use the street-side shutoff instead and have the interior valve replaced when the emergency is resolved.

Test Your Valve Annually

Shutoff valves that sit unused for years often seize from mineral deposits and corrosion. Testing your main shutoff once a year ensures it will work when you need it. Turn the valve off, verify that water stops flowing at a faucet, then turn it back on.

If the valve is difficult to turn, leaks when operated, or does not fully stop the water, have it replaced before an emergency forces the issue. A valve replacement is a relatively quick and affordable job that pays for itself the first time you need it.

Fixture-Level Shutoffs

In addition to the main shutoff, most fixtures have individual shutoff valves. Toilets have a shutoff on the wall behind or beside the unit. Sinks typically have two shutoffs under the cabinet — one for hot and one for cold. Washing machines have shutoffs behind the unit.

For a localized leak, using the fixture-level shutoff lets you stop the water to the affected fixture without cutting off water to the entire house. Test these periodically as well.